Packaging structure and method of packaging tunable laser device, and tunable laser device

ABSTRACT

The present disclosure provides a packaging structure and a method of packaging an tunable laser device, and an tunable laser device. The packaging structure of the tunable laser device may include a TO tube base and a TO tube cap, wherein a first thermal sink is disposed on the TO tube base, a semiconductor laser chip is disposed on a vertical side of the first thermal sink, an aspheric lens is disposed on the TO tube cap, and the semiconductor laser chip is disposed on a central axis of the aspheric lens; and wherein the vertical side of the first thermal sink is a side of the first thermal sink perpendicular to the TO tube base. The tunable laser device according to the present disclosure may be applicable to communication over an optical fiber.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit and priority of Chinese PatentApplication No. 201410433096.0 filed Aug. 28, 2014. The entiredisclosure of the above application is incorporated herein by reference.

FIELD

The present disclosure relates to the technical field of laser devicesand particularly to a packaging structure and a method of packaging atunable laser device and a tunable laser device.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

Laser has been widely applied in optical fiber communication systems,due to its high directivity, high coherence, high monochrome and othersignificant advantages. At present, laser is typically generated by alaser device at a constant wavelength, which can only generate laser atthe constant wavelength, but there is an increasing demand for laser atdifferent wavelengths in the optical fiber communication systems, due tothe development of Dense Wavelength Division Multiplexing (DWDM)technology, so that a large number of laser devices at the differentconstant wavelengths have to be provided, thus resulting in a growingnumber of laser devices and an increase in cost thereof.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.

In an aspect, an embodiment of the present disclosure provides apackaging structure of an tunable laser device, including: a TO tubebase and a TO tube cap, herein a first thermal sink is disposed on theTO tube base, a semiconductor laser chip is disposed on a vertical sideof the first thermal sink, an aspheric lens is disposed on the TO tubecap, and the semiconductor laser chip is disposed on a central axis ofthe aspheric lens; and herein the vertical side of the first thermalsink is a side of the first thermal sink perpendicular to the TO tubebase.

In another aspect, an embodiment of the present disclosure provides amethod for packaging an tunable laser device, and the tunable laserdevice includes: a semiconductor laser chip, a first thermal sink, anaspheric lens, a TO tube base, and a TO tube cap; the packaging methodincluding:

soldering the semiconductor laser chip on a vertical side of the firstthermal sink through eutectic soldering, which is a side of the firstthermal sink perpendicular to the TO tube base;

soldering the first thermal sink on the TO tube base through eutecticsoldering;

connecting the above soldered components with pins of the TO tube basethrough gold-wire soldering;

soldering the aspheric lens on the TO tube cap; and

soldering the TO tube cap soldered with the aspheric lens on the TO tubebase.

In still another aspect, an embodiment of the present disclosureprovides an tunable laser device including a packaging structureincluding a TO tube base and a TO tube cap, herein a first thermal sinkis disposed on the TO tube base, a semiconductor laser chip is disposedon a vertical side of the first thermal sink, an aspheric lens isdisposed on the TO tube cap, and the semiconductor laser chip isdisposed on a central axis of the aspheric lens; and herein the verticalside of the first thermal sink is a side of the first thermal sinkperpendicular to the TO tube base.

Further aspects and areas of applicability will become apparent from thedescription provided herein. It should be understood that variousaspects of this disclosure may be implemented individually or incombination with one or more other aspects. It should also be understoodthat the description and specific examples herein are intended forpurposes of illustration only and are not intended to limit the scope ofthe present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 illustrates a schematic diagram of a packaging structure inside awavelength-adjustable semiconductor laser device;

FIG. 2 illustrates a schematic diagram of a packaging structure outsidea tunable laser device according to embodiments of the presentdisclosure;

FIG. 3 illustrates a schematic diagram of the packaging structure of thetunable laser device as illustrated in FIG. 2;

FIG. 4 illustrates a schematic diagram of a packaging structure inside atunable laser device according to embodiment of the present disclosure;

FIG. 5 illustrates a schematic diagram of an inside structure of asemiconductor laser chip in which a DBR is disposed;

FIG. 6 illustrates a schematic diagram of a correspondence relationshipbetween current injected into the DBR and an output wavelength; and

FIG. 7 illustrates a schematic diagram of the disposition of pins of thetunable laser device as illustrated in FIG. 4.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

The technical solutions according to some embodiments of the presentdisclosure will be described below with reference to the drawings inembodiments of the present disclosure, and apparently embodimentsdescribed here are merely a part but not all of embodiments of thepresent disclosure. All the other embodiments which can occur to thoseordinarily skilled in the art based upon embodiments of the presentdiscourse without any inventive effort shall fall into the scope of thepresent disclosure as claimed.

In order to address the problem of a large number of laser devices atdifferent constant wavelengths to be provided in an optical fibercommunication system, an embodiment of the present disclosure provides awavelength-adjustable semiconductor laser device, and FIG. 1 illustratesa schematic diagram of a packaging structure of thewavelength-adjustable semiconductor laser device. Forward light of asemiconductor laser chip 105 passing through an aspheric lens 107 isturned into a collimated spot, and the collimated spot reflected by aright-angled lens 108 is changed in direction by 90°, and then exitsfrom a window film 109 on the surface of a TO tube cap 110 in thedirection perpendicular to a TO tube base 101. Backward light of thesemiconductor laser chip 105 is projected directly onto an photoelectricdiode 106, to detect output power of the semiconductor laser chip 105;and a thermally conductive sheet 104 is configured to ensure the forwardoptical center of the semiconductor laser chip 105 and the center of theaspheric lens 107 to be located on the same horizontal line, i.e.,collimated coaxially. The optical elements above are placed sequentiallyon a platform 103, and then on a thermoelectric cooler (TEC) 102, andfinally the thermoelectric cooler 102 is placed on the upper surface ofthe TO tube base 101, and the TO tube cup 110 and the TO tube base 101are adhered together by an adhesive, thus a packaging structure of thewavelength-adjustable semiconductor laser device is formed.

However, the inventors have identified that in the process of packagingthe wavelength-adjustable semiconductor laser device, the forward lightof the semiconductor laser chip 105 is converged, by the aspheric lens107, into the collimated spot, and only after being refracted by theright-angled lens 108, can the collimated spot exit perpendicular to thedirection of the TO tube base 101; that is, the forward light of thesemiconductor laser chip 105 can exit perpendicularly only after beingrefracted by the right-angled lens 108.

Embodiments of the present disclosure provide a packaging structure anda method of packaging a tunable laser device, and a tunable laserdevice.

Some embodiments of the present disclosure provide a packaging structureand a method of packaging a tunable laser device, and a tunable laserdevice, and the packaging structure includes a TO tube base and a TOtube cap, a first thermal sink disposed on the TO tube base, asemiconductor laser chip disposed on a vertical side of the firstthermal sink, and an aspheric lens disposed on the TO tube cap, hereinthe semiconductor laser chip is disposed on a central axis of theaspheric lens, and the vertical side of the first thermal sink is a sideof the first thermal sink perpendicular to the TO tube base. Since thevertical side of the first thermal sink is perpendicular to the TO tubebase, and the semiconductor laser chip is disposed on the vertical sideof the first sink, so that the semiconductor laser chip is perpendicularto the TO tube base; and also since the semiconductor laser chip isdisposed on the central axis of the aspheric lens, forward light exitingthe semiconductor laser chip is collimated by the aspheric lens and thenexits the aspheric lens, and the forward light is perpendicular to theTO tube base. Thus the forward light of the semiconductor laser chip inembodiments of the present disclosure can pass the aspheric lens on theTO tube cap and directly exit perpendicular to the TO tube base; and theforward light of the semiconductor laser chip passing the aspheric lenscan exit perpendicular to the TO tube base without passing aright-angled lens, to thereby address such a problem in the packagingstructure of the tunable laser device that only after being refracted bythe right-angled lens can the forward light of the semiconductor laserchip can exit perpendicularly.

As illustrated in FIG. 2, an embodiment of the present disclosureprovides a packaging structure outside a tunable laser device, and thetunable laser device includes a TO tube base 201 and a TO tube cap 208.

Pins 209 are disposed on the TO tube base 201 to be connectable with anexternal circuit, to thereby monitor an operating state of the tunablelaser device; and an aspheric lens 210 disposed on the TO tube cup 208can converge forward light, generated by a semiconductor laser chip 205inside the tunable laser device, into collimated light to be coupledinto an optic fiber for transmission.

FIG. 3 illustrates a schematic diagram of the packaging structure of thetunable laser device as illustrated in FIG. 2. As can be apparent fromFIG. 3, a first thermal sink 203 is disposed on the TO tube base 201,the semiconductor laser chip 205 is disposed on a vertical side of thefirst thermal sink 203, and the semiconductor laser chip 205 is disposedon the central axis of the aspheric lens 210, herein the forward lightof the semiconductor laser chip 205 is directed in the direction pointedto by the arrow in FIG. 3, and the vertical side of the first thermalsink 203 is a side of the first thermal sink 203 perpendicular to the TOtube base 201.

The first thermal sink 203 as illustrated in FIG. 3 may be made of metalor ceramic, which can be metalized on the surface thereof, with athermal conductivity above 180 W/mk and a thermal expansion coefficientbelow 8*10-6° C. For example, the first thermal sink 203 may be embodiedas a tungsten-cooper thermal sink. Since the first thermal sink 203 isprovided with a horizontal side and a vertical side respectively, it maybe designed in an L-shaped structure, for example. Since the verticalside of the first thermal sink 203 in the L-shaped structure isperpendicular to the TO tube base 201, the semiconductor laser chip 205is disposed on the vertical side of the first thermal sink 203 in theL-shaped structure, so that the forward light of the semiconductor laserchip 205 may exit perpendicular to the TO tube base 201. Also due to thehigh thermal conductivity of the first thermal sink 203, the firstthermal sink 203 in the L-shaped structure may be further configured toconduct the heat generated by the semiconductor laser chip 205 disposedthereon.

Some embodiments of the present disclosure provide a packaging structureand a method of packaging a tunable laser device, and the packagingstructure includes a TO tube base and a TO tube cup, a first thermalsink disposed on the TO tube base, a semiconductor laser chip disposedon a vertical side of the first thermal sink, and an aspheric lensdisposed on the TO tube cap, herein the semiconductor laser chip isdisposed on a central axis of the aspheric lens, and the vertical sideof the first thermal sink is a side of the first thermal sinkperpendicular to the TO tube base. Since the vertical side of the firstthermal sink is perpendicular to the TO tube base, and the semiconductorlaser chip is disposed on the vertical side of the first sink, so thatthe semiconductor laser chip is perpendicular to the TO tube base; andalso since the semiconductor laser chip is disposed on the central axisof the aspheric lens, forward light exiting the semiconductor laser chipis collimated by the aspheric lens and then exits the aspheric lens, andthe forward light is perpendicular to the TO tube base. Thus the forwardlight of the semiconductor laser chip in embodiments of the presentdisclosure may pass the aspheric lens on the TO tube cap and directlyexit perpendicular to the TO tube base; and the forward light of thesemiconductor laser chip passing the aspheric lens may exitperpendicular to the TO tube base without passing a right-angled lens,to thereby address such a problem in the packaging structure of thetunable laser device that only after being refracted by the right-angledlens, can the forward light of the semiconductor laser chip exitperpendicularly.

With the tunable laser device according to some embodiments of thepresent disclosure, the aspheric lens is disposed on the TO tube cup,and thus there is no need to dispose the aspheric lens inside thetunable laser device; and also the tunable laser device according tosome embodiments of the present disclosure does not have to be providedwith a right-angled lens, so there is no need to dispose theright-angled lens inside the tunable laser device, thus shrinking thepackage size of the laser device, and reducing the producing cost andthe manufacturing difficulty.

The packaging structure of the tunable laser device according to anembodiment of the present disclosure can further include a secondthermal sink 204. The semiconductor laser chip 205 is disposed on thesecond thermal sink 204, and the second thermal sink 204 with thesemiconductor laser chip 205 disposed thereon is disposed on thevertical side of the first thermal sink.

The second thermal sink 204 may be made of metal or ceramic, which maybe metalized on the surface thereof, with a thermal conductivity above220 W/mk and a thermal expansion coefficient of approximately 4.5*10-6°C. For example, in an embodiment of the present disclosure, the secondthermal sink 204 is made of Aluminum Nitride (ALN). Since the thermalconductivity of the second thermal sink 204 is higher than the thermalconductivity of the first thermal sink 203, the heat generated by thesemiconductor laser chip 205 may be conducted from the second thermalsink 204 to the first thermal slink 203 more rapidly; and the contactarea of the second thermal sink 204 with the first thermal sink 203 islarger than the contact area of the semiconductor laser chip 205 withthe first thermal sink 203, to thereby facilitate heat dissipation ofthe semiconductor laser chip 205.

Optionally, the first thermal sink 203 and the second thermal sink 204may be made as large as possible while accommodating the conventionalsize of the TO package, to thereby improve the efficiency of heatdissipation of the semiconductor laser chip 205; and also the size andthe performance of the thermoelectric cooler 202 may be designed toaccommodate the small size of the TO package while achieving the optimumcooling efficiency and the lowest power consumption thereof.

Optionally, as illustrated in FIG. 4, in order to monitor the power ofthe forward light exiting the tunable laser device, the packagingstructure of the tunable e laser device may further include a backlightmonitor 207 disposed on the horizontal side of the first thermal sink203, herein the horizontal side of the first thermal sink 203 is a sideof the first thermal sink parallel to the TO tube base 201.

For example, the backlight monitor 207 may be embodied as a backlightmonitor diode configured to monitor the power of the forward lightexiting the semiconductor laser chip. After backward light of thesemiconductor laser chip 205 is projected onto the backlight monitordiode, the backlight monitor diode may generate light current from thebackward light, so that the higher the intensity of the light, thelarger the generated light current will be. With reference to themagnitude of the light current and the ratio of the light beforeexisting to the light after existing the semiconductor laser chip 205,the power of the forward light exiting the semiconductor laser chip 205may be monitored in real time, and the power of the forward lightexiting the semiconductor laser chip 205 may be automatically adjustedto the change in current of the backward light.

In order to improve the effect of heat dissipation of the semiconductorlaser chip, the packaging structure of the tunable laser device mayfurther include a thermoelectric cooler 202. As illustrated in FIG. 4,the horizontal side of the first thermal sink 203 is disposed on thethermoelectric cooler 202, and the thermoelectric cooler 202 is disposedon the TO tube base 201.

The heat generated by the semiconductor laser chip 205 is conducted tothe first thermal sink 203 through the second thermal sink 204, and thento the cool end of the thermoelectric cooler 202 through the firstthermal sink 203, so that the heat is conducted to the outside throughthe TO tube base 201, due to the Peltier effect of the thermoelectriccooler 202. It shall be noted that the Peltier effect refers to such aphenomenon that the cool end of the thermoelectric cooler absorbs heat,and the thermal end thereof releases heat, when DC current passes thethermoelectric cooler. Since the heat is conducted through the materialwith a high thermal conductivity throughout the thermal conductionprocess, there is a very small thermal resistance between thesemiconductor laser chip 205 and the TO tube base 201, to therebyachieve a high thermal conductivity.

In order to detect in real time a change in temperature of the tunablelaser chip, the packaging structure of the tunable laser device mayfurther include a temperature sensor 206. In the packaging structure ofthe tunable laser device without the second thermal sink 204, thetemperature sensor 206 may be disposed on the first thermal sink 203;and in the packaging structure of the tunable laser device includingboth the first thermal sink 203 and the second thermal sink 204, thetemperature sensor 206 may be disposed on the second thermal sink 204.FIG. 4 illustrates the example where the temperature sensor 206 isdisposed on the second thermal sink 204.

No matter the temperature sensor 206 is disposed on the first thermalsink 203 or the second thermal sink 204, the distance between thetemperature sensor 206 and the semiconductor laser chip 205 may be setbetween 30 μm and 200 μm. For example, the distance between thetemperature sensor 206 and the semiconductor laser chip 205 can be setto be 50 μm, 60 μm, 80 μm, 100 μm, 120 μm or 140 μm. For example, thedistance between the semiconductor laser chip 205 and the temperaturesensor 206 may be set to be 100 μm in a preferred embodiment of thepresent disclosure.

In another example, the temperature sensor 206 may be a thermallysensitive resistor. Since the resistance of the thermally sensitiveresistor may vary with temperature, so that a different resistancethereof corresponds to different temperature, and the resistance of thethermally sensitive resistor may vary with temperature up to theprecision of 1%, the thermally sensitive resistor can be disposed closeto the semiconductor laser chip 205, to thereby reflect precisely thechange in temperature of the semiconductor laser chip 205.

The temperature of the semiconductor laser chip 205 may further beadjusted by the thermoelectric cooler 202 and the thermally sensitiveresistor inside the packaging structure of the tunable laser device, andan Automatic Temperature Control (ATC) circuit outside the packagingstructure of the tunable laser device. Since the temperature of thesemiconductor laser chip 205 is fed back precisely by the resistance ofthe thermally sensitive resistor, the ATC circuit may acquire theresistance of the thermally sensitive resistor, to monitor thetemperature of the semiconductor laser chip 205, and the ATC circuit mayapply current rapidly to the thermoelectric cooler 202 in response tothe change in resistance of the thermally sensitive resistor, to therebystabilize the temperature of the semiconductor laser chip 205 throughheating or cooling, so as to stabilize and adjust the temperaturethereof.

A Distributed Bragg Reflector (DBR) is disposed in the semiconductorlaser chip according to the embodiments of the present disclosure. Withthe characteristic of the DBR, a wavelength may be adjustablecontinuously, by changing the magnitude of current injected into the DBRand adjusting the temperature of the DBR, herein FIG. 5 illustrates aschematic structural diagram inside a semiconductor laser chip in whicha DBR is disposed, and as can be apparent from FIG. 5, the chipgenerally includes an active area 301, a phase control area 302 and aBragg reflective grating area 303 (also referred to as a DBR area). Theconcentration of carriers in the DBR area and the reflectivity thereofwill vary, with varying current injected into the DBR area, so that acentral wavelength generated therein will vary. As illustrated in FIG.6, as the current in the DBR area increments, the central wavelengthgenerated by the semiconductor laser chip 205 tends to decrease in astepped manner by a step of approximately 0.8 nanometer (nm), and thisadjustment will be referred to as rough adjustment, due to a significantinfluence of the variation in change on the variation in outputwavelength. Moreover as can be apparent from FIG. 6, the outputwavelength decreases at a rate which becomes lower gradually along withthe increase of the current, until the current increases to 20milli-amperes (mA), and then the output wavelength remains substantiallyconstant, so the wavelength can be adjusted by approximately 10 nmthrough varying the current in the DBR area.

Moreover, with given constant current injected into the DBR area, theactive area of the DBR will impose an influence upon the centralwavelength generated by the semiconductor laser chip varying withtemperature, herein the coefficient of the central wavelength varyingwith temperature ranges from 0.1 to 0.12 nm/° C., and the ATC circuitcan control the temperature to be adjusted to the precision of 0.01° C.,so the temperature may be controlled precisely, to thereby control thecentral wavelength, generated by the tunable laser chip with the DBRdisposed therein, to be varied between approximately 0.001 nm to 0.0012nm, and this adjustment may be referred to as fine adjustment. Since theoperating temperature of the tunable laser chip with the DBR disposedtherein ranges from 25 to 50° C., the operating temperature of thetunable laser chip with the DBR disposed therein can be tunable between25 and 50° C., and varied by 25° C. at most, so the temperature can betunable to thereby adjust the wavelength in the range of approximately2.5 to 3 nm.

Thus in combination of the rough adjustment and the fine adjustment, thecentral wavelength of the tunable laser chip with the DBR disposedtherein may be adjusted by more than 12 nm, and Table 1 belowexperimentally depicts an example of a varying central wavelength of antunable laser device, adjustable at 16 channel wavelengths, as specifiedin compliance with the International Telecommunication Union (ITU)

TABLE 1 Frequency Wavelength 16 channels (THz) (nm) 1 192.2 1559.79 2192.3 1558.98 3 192.4 1558.17 4 192.5 1557.36 5 192.6 1556.55 6 192.71555.75 7 192.8 1554.94 8 192.9 1554.13 9 193.0 1553.33 10 193.1 1552.5211 193.2 1551.72 12 193.3 1550.92 13 193.4 1550.12 14 193.5 1549.32 15193.6 1548.51 16 193.7 1547.72

FIG. 7 illustrates a top view of the tunable laser device as illustratedin FIG. 4. As can be apparent from FIG. 7, the tunable laser deviceincludes 7 pines, herein the pin 501 and the pine 502 are respectivelyconnected with an anode and a cathode of the thermoelectric cooler, thepin 503 is connected with a cathode of the backlight monitor diode, thepin 504 is connected with one end of the thermally sensitive resistor,the pin 505 is a grounded pin and can be used as a cathode of the activearea of the DBR, a cathode of the grating area of the DBR, an anode ofthe backlight monitor diode, and the other terminal of the thermallysensitive resistor, the pin 506 is connected with an anode of the activearea of the DBR, and the pin 507 is connected with an anode of thegrating area of the DBR.

It shall be noted that FIG. 4 illustrates merely a schematic structuraldiagram inside of an optional tunable laser device according to someembodiments of the present disclosure, and the tunable laser deviceincludes both the first thermal sink and the second thermal sink, sothat the heat generated by the semiconductor laser chip may be conductedrapidly to the outside through the first thermal sink and the secondthermal sink, to thereby achieve a high thermal conductivity. FIG. 7illustrates merely a schematic diagram of the disposition of the pins,but the pins may alternatively be disposed otherwise without departingfrom the scope of embodiments of the disclosure as claimed, optionallyat least 8 pins can be included, of which 7 pins may be embodied thesame as the pins as illustrated in FIG. 7, and the remaining pin can beused as a reserved pin for later use.

Some embodiments of the present disclosure provide a method of packagingan tunable laser device including a TO tube base, a TO tube cap, a firstthermal sink, a semiconductor laser chip, and an aspheric lens, and themethod of packaging the tunable laser device includes:

The semiconductor laser chip may be soldered on a vertical side of thefirst thermal sink through eutectic soldering, herein the vertical sideof the first thermal sink is a side of the first thermal sinkperpendicular to the TO tube base; the first thermal sink may besoldered on the TO tube base through eutectic soldering; the abovesoldered components may be connected with pins of the TO tube basethrough gold-wire soldering; the aspheric lens may be soldered on the TOtube cap; and the TO tube cap soldered with the aspheric lens may besoldered on the TO tube base.

Optionally, the eutectic soldering may be performed by using a gold-tinsolder with a melting point of approximately 280° C.; and the TO tubecap may be soldered on the TO tube base, and the TO tube cap may befused and sealed on the TO tube base using resistance soldering and asolder.

The tunable laser device may further include a thermoelectric cooler, atemperature sensor, and a backlight monitor, and the method of packagingthe tunable laser device can include:

The semiconductor laser chip and the temperature sensor are solderedthrough eutectic soldering on the vertical side of the first thermalsink; the backlight monitor is adhered on a horizontal side of the firstthermal sink; the first thermal sink is soldered through eutecticsoldering on the thermoelectric cooler; the thermoelectric cooler issoldered through eutectic soldering on the TO tube base; the abovesoldered components are connected with the pins of the TO tube basethrough gold-wire solder; the aspheric lens is soldered on the TO tubecup; and the TO tube cup soldered with the aspheric lens is soldered onthe TO tube base, herein the vertical side of the first thermal sink isa side of the first thermal sink perpendicular to the TO tube base, andthe horizontal side of the first thermal sink is a side of the firstthermal sink parallel to the TO tube base.

Optionally, the backlight monitor may be adhered on the horizontal sideof the first thermal sink through a silver adhesive.

When the tunable laser device further includes a second thermal sink,the method of packaging the tunable laser device may include:

The semiconductor laser chip and the temperature sensor are solderedthrough eutectic soldering on the second thermal sink; the secondthermal sink is soldered through eutectic soldering on the vertical sideof the first thermal sink, and the backlight monitor is adhered on thehorizontal side of the first thermal sink; the first thermal sink issoldered through eutectic soldering on the thermoelectric cooler; thethermoelectric cooler is soldered through eutectic soldering on the TOtube base; the above soldered components are connected with the pins ofthe TO tube base through gold-wire solder; and the TO tube cup issoldered on the TO tube base, herein the vertical side of the firstthermal sink is a side of the first thermal sink perpendicular to the TOtube base, and the horizontal side of the first thermal sink is a sideof the first thermal sink parallel to the TO tube base.

Moreover, some embodiments of the present disclosure further provide antunable laser device including a packaging structure which may include aTO tube base and a TO tube cap, herein a first thermal sink is disposedon the TO tube base, a semiconductor laser chip is disposed on avertical side of the first thermal sink, an aspheric lens is disposed onthe TO tube cap, and the semiconductor laser chip is disposed on acentral axis of the aspheric lens; and herein the vertical side of thefirst thermal sink is a side of the first thermal sink perpendicular tothe TO tube base.

Optionally, the packaging structure above may further include a secondthermal sink, herein the semiconductor laser chip is disposed on thesecond thermal sink, and the second think is disposed on the verticalside of the first thermal sink.

Optionally, the packaging structure above may further include abacklight monitor disposed on a horizontal side of the first thermalsink, which is a side of the first thermal sink parallel to the TO tubebase.

Optionally, the packaging structure above may further include athermoelectric cooler, herein the horizontal side of the first thermalsink is disposed on the thermoelectric cooler, and the thermoelectriccooler is disposed on the TO tube base.

Optionally, the packaging structure above may further include atemperature sensor disposed on the first thermal sink.

Optionally, the packaging structure above may further include at least 7pins disposed on the TO tube base.

Lastly, it shall be noted that embodiments above are merely illustrativethe technical solutions of the present disclosure but not intended tolimit them; and although the present disclosure has been described indetails with reference to embodiments above, those ordinarily skilled inthe art shall appreciate that they can modify the technical solutionsaccording to the respective embodiments above or make equivalentsubstitutions to a part of the technical features thereof; and thesemodifications or substitutions can be made to the respective technicalsolutions without departing from the spirit and scope of the technicalsolutions according to the respective embodiments of the presentdisclosure.

1. A packaging structure of an tunable laser device, comprising a TOtube base and a TO tube cap, a first thermal sink is disposed on the TOtube base, a semiconductor laser chip is disposed on a vertical side ofthe first thermal sink, an aspheric lens is disposed on the TO tube cap,and the semiconductor laser chip is disposed on a central axis of theaspheric lens; and wherein the vertical side of the first thermal sinkis a side of the first thermal sink perpendicular to the TO tube base.2. The packaging structure according to claim 1, the packaging structurefurther comprises: a second thermal sink, wherein the semiconductorlaser chip is disposed on the second thermal sink, and the second thinkis disposed on the vertical side of the first thermal sink.
 3. Thepackaging structure according to claim 1, the packaging structurefurther comprises: a backlight monitor disposed on a horizontal side ofthe first thermal sink, which is a side of the first thermal sinkparallel to the TO tube base.
 4. The packaging structure according toclaim 1, the packaging structure further comprises: a thermoelectriccooler, wherein the horizontal side of the first thermal sink isdisposed on the thermoelectric cooler, and the thermoelectric cooler isdisposed on the TO tube base.
 5. The packaging structure according toclaim 1, the packaging structure further comprises: a temperature sensordisposed on the first thermal sink.
 6. The packaging structure accordingto claim 2, the packaging structure further comprises: a temperaturesensor disposed on the second thermal sink.
 7. The packaging structureaccording to claim 1, the packaging structure further comprises: atleast 7 pins disposed on the TO tube base.
 8. A method of packaging antunable laser device comprising a semiconductor laser chip, a firstthermal sink, an aspheric lens, a TO tube base, and a TO tube cap, thepackaging method comprises: soldering the semiconductor laser chip on avertical side of the first thermal sink, which is a side of the firstthermal sink perpendicular to the TO tube base; and soldering the firstthermal sink on the TO tube base; connecting above soldered componentswith pins of the TO tube base; soldering the aspheric lens on the TOtube cap; and soldering the TO tube cap soldered with the aspheric lenson the TO tube base.
 9. The packaging method according to claim 8, thetunable laser device further comprises a temperature sensor, a backlightmonitor, and a thermoelectric cooler, and the soldering the firstthermal sink on the TO tube base comprises: soldering the temperaturesensor on the vertical side of the first thermal sink; adhering thebacklight monitor on a horizontal side of the first thermal sink,wherein the horizontal side of the first thermal sink is a side of thefirst thermal sink parallel to the TO tube base; soldering the firstthermal sink on the thermoelectric cooler; and soldering thethermoelectric cooler on the TO tube base.
 10. The packaging methodaccording to claim 9, wherein the tunable laser device further comprisesa second thermal sink; and the soldering the temperature sensor on thevertical side of the first thermal sink comprises: soldering thetemperature sensor on the second thermal sink; and soldering the secondthermal sink on the vertical side of the first thermal sink.
 11. Antunable laser device, comprising a packaging structure comprising a TOtube base and a TO tube cap, wherein a first thermal sink is disposed onthe TO tube base, a semiconductor laser chip is disposed on a verticalside of the first thermal sink, an aspheric lens is disposed on the TOtube cap, and the semiconductor laser chip is disposed on a central axisof the aspheric lens; and wherein the vertical side of the first thermalsink is a side of the first thermal sink perpendicular to the TO tubebase.
 12. The tunable laser device according to claim 11, wherein thetunable laser device comprises a second thermal sink, the semiconductorlaser chip is disposed on the second thermal sink, and the second thinkis disposed on the vertical side of the first thermal sink.
 13. Thetunable laser device according to claim 11, wherein the tunable laserdevice comprises a backlight monitor disposed on a horizontal side ofthe first thermal sink, which is a side of the first thermal sinkparallel to the TO tube base.
 14. The tunable laser device according toclaim 11, wherein the tunable laser device comprises a thermoelectriccooler, wherein the horizontal side of the first thermal sink isdisposed on the thermoelectric cooler, and the thermoelectric cooler isdisposed on the TO tube base.
 15. The tunable laser device according toclaim 11, wherein the tunable laser device comprises a temperaturesensor disposed on the first thermal sink.
 16. The tunable laser deviceaccording to claim 12, wherein the tunable laser device comprises atemperature sensor disposed on the second thermal sink.
 17. The tunablelaser device according to claim 11, wherein the tunable laser devicecomprises at least 7 pins disposed on the TO tube base.